Energy Budget in the High Energy Universe

Preface.

CONTENTS.

The Akeno Giant Air Shower Array (AGASA) had observed 11 events of Extremely-High Energy Cosmic Rays (EHECRs) with energies exceeding 10²⁰eV. The energy of these cosmic rays is beyond the Gleisen-Zatsepin-Kuzmin (GZK) cutoff expected by the interaction of EHE protons with the Cosmic Microwave Background (CMB). New experiments with much larger acceptance and improved energy determination, Telescope Array (TA) experiment and Pierre Auger observatory are being built to confirm the existence of EHECRs and to understand their origin.

The High Resolution Fly's Eye (HiRes) Experiment has been in operation in monocular mode since 1997. The HiRes results on the cosmic ray spectrum are consistent with the GZK Suppression at 10^19.8 eV and observes an ankle structure at 10^18.5 eV. Composition studies of Hires stereo data shows a predominantly light composition in the energy range 10^18.0 – 10^19.3 eV. We also report on the result of the proton-air cross section measurement from the tails of the X_MAX distribution. Various anisotropy studies have yielded null results. However, an apparent correlation between HiRes stereo events and BL-Lac objects has been reported.

Theoretical aspects of potential astrophysical sources of the highest energy cosmic rays are discussed, including their energy budget and issues on particle escape and propagation. We highlight the possibility of heavy nuclei originating from cluster accretion shocks. The importance of X-ray and gamma-ray signatures in addition to neutrinos as diagnostic tools for source identification is emphasized.

Diffuse radio emission from galaxy clusters indicates the presence of GeV electrons and microgauss level magnetic fields in the intracluster medium (ICM). Nonthermal emission due to Inverse Compton scattering of relativistic electrons off the cosmic microwave background radiation (CMBR) has been also detected in several clusters. Considering that most acceleration mechanisms preferentially accelerate more protons than electrons, we can deduce that the energy contained in CR protons could be even more substantial. We review the possible astrophysical sources that can inject and accelerate CRs, and generate and amplify magnetic fields in the ICM. From both observational and theoretical grounds, we conclude that the energy budget of CR protons, magnetic fields, and turbulence is each order of 10 % of thermal energy, while CR electrons may contain less than 1 % of thermal energy.

We describe our investigative work observing microwave emission from ultra-high energy cosmic ray (UHECR) extensive air showers. This work has consisted primarily of RF observations made at accelerator facilities and the deployment of an atmospheric detector in Honolulu, Hawai‘i. While this technique appears promising, further verification will be needed in the form of coincident observations with an already accepted method for UHECR detection.

Several kinds of measurements are combined in an attempt to obtain a consistent estimate of the spectrum and composition of the primary cosmic radiation through the knee region. Assuming that the knee is a signal of the high-energy end of a galactic cosmic-ray population, I discuss possible signatures of a transition to an extra-galactic population and how they might be detected.

AMS-02 is a space borne magnetic spectrometer designed to measure with accuracies up to one part in 10⁹ the composition of Cosmic Rays near Earth. With a large acceptance (5000 cm² sr), an intense magnetic field from a superconducting magnet (0.7 T) and an accurate particle identifications AMS-02 will provide the highest accuracy in Cosmic Rays measurements up to the TeV region. During a three years long mission on the ISS AMS-02 will achieve a sensitivity to the existence of anti-He in the Cosmic Rays of one part in a billion as well as important informations on the origin of Dark Matter. We review the status of the construction of the AMS-02 experiment in preparation for the three years mission on the ISS.

Although kilometer-scale neutrino detectors such as IceCube are discovery instruments, their conceptual design is very much anchored to the observational fact that Nature produces protons and photons with energies in excess of 10²⁰ eV and 10¹³ eV, respectively. The puzzle of where and how Nature accelerates the highest energy cosmic particles is unresolved almost a century after their discovery. We will discuss how the cosmic ray connection sets the scale of the anticipated cosmic neutrino fluxes. In this context, we discuss the first results of the completed AMANDA detector and the science reach of its extension, IceCube.

Neutrinos at energies ranging from sub-TeV to EeV from astrophysical sources can yield interesting physical information about fundamental interactions, about cosmic rays and about the nature of the sources and their environment. Gamma-ray bursts are a leading candidate source, and their expected neutrino emission can address a number of current questions, which may be answered with forthcoming experiments such as IceCube, Auger, ANITA and KM3NeT.

The BESS experiment precisely measured cosmic-ray flux in the energy range below 1 TeV with a high-precision, magnetic-rigidity spectrometer. It has provided fundamental cosmic-ray data, and has extended search for low energy antiparticle of novel cosmic origins. The BESS-Polar program is being carried out with long duration flight in Antarctica to realize unprecedented sensitivity in low energy cosmic-ray observation. This report describes recent results from BESS and the progress in the BESS-Polar program.

PAMELA is a satellite-borne experiment with the main purpose to measure the antiparticle component of cosmic rays over an extended energy range (80 MeV – 190 GeV for and 50 MeV – 270 GeV for e⁺) and with unprecedented accuracy. Other physics objectives are the measurement of the galactic, heliospheric and trapped components of cosmic rays (80 MeV – 700 GeV for p, 50 MeV – 400 GeV for e⁻). The apparatus consists of a permanent magnetic spectrometer equipped with a double-sided silicon microstrip tracking system and surrounded by a scintillator anticoincidence system. A silicon-tungsten imaging calorimeter, complemented by a scintillator shower tail catcher performs the particle identification task. Fast scintillators are used for Time-of-Flight measurements and to provide the primary trigger. A neutron detector improves the particle identification, extends the range of particle measurements to the TeV region and allows to study solar and trapped neutron component. In this work we will focus on the description of the observational characteristics of the detector in the field of solar, heliospheric and trapped cosmic rays.

The acceleration of high energy particles in astrophysical sources has attracted our attention for a long time, and their origins remain a central problem in astroplasma physics. We review recent progress that was made to understand both the dynamic structure of the source region and the connection with particle acceleration, and specifically discuss that not only the stochastic acceleration such as the first order Fermi acceleration, but also the direct acceleration seen in the shock front or in the reconnection region can contribute to the origins of the astrophysical nonthermal particles.

Since its launch on 20 November 2004, the Swift mission is detecting ~100 new gamma-ray bursts (GRBs) each year, and immediately (within two minutes) starting simultaneous X-ray and UV/optical observations of the afterglow. It has already collected am impressive database of bursts, including prompt emission to higher sensitivity than BATSE, uniform monitoring of afterglows, and rapid follow-up by other observatories notified through the GCN.

Highlights of the recent observations of gamma-ray bursts are presented. In the optical afterglow of GRB030329 detected by HETE-2, strong evidence for the association of long GRBs with the core-collapse supernovae was found. With the wide energy coverage, the nature of the X-ray rich GRBs and X-ray flashes have been studied systematically with HETE-2, and they are found to have many properties in common with the classical GRBs, suggesting that they are a single phenomenon. In July 2005, HETE-2 localized a short gamma-ray burst GRB 050709, which led to the discovery of the first optical afterglow of a short GRB in a low-redshift galaxy, providing evidence that the origins of most short GRBs are different from those of long GRBs. The extremely intense flare of the soft gamma repeater SGR 1806–20 was observed in December 2004. The possible connection with the short population GRBs are discussed.

Gamma-Ray bursts (GRBs) are considered to be one of the most promising sources of ultra-high energy cosmic rays (UHECRs), detectable neutrino flux and bright GeV photons. Here I briefly review the theoretical predictions for the production of these types of emission in GRBs.

We have done 2-dimensional MHD simulation of collapsars with magnetic fields and neutrino cooling/heating processes. It is found that explosion energy of a hypernova is not obtained from the neutrino heating process. However, strong jet is found when magnetic fields are included, and total energy of the jet component can be of the order of 10⁵² erg, which is comparable to the one of a hypernova.

The CANGAROO-III telescope system for very-high-energy gamma-ray astrophysics consists of four 10 m atmospheric Cherenkov telescopes located near Woomera, South Australia. The construction of the fourth telescope was completed in summer 2003, and stereoscopic observations has been in progress since March 2004. Here we report on the status of the system and some recent results from CANGAROO-III observations.

H.E.S.S. results from the first three years of nominal operation are presented. Among the many exciting measurements that have been made, most gamma-ray sources are of Galactic origin. I will concentrate here on an overview of Galactic observations and summarise and discuss observations of selected objects of the different source types.

We give an overview on the theoretical description of individual supernova remnants (SNRs) as particle accelerators and report about the latest developments regarding Tycho's SN, SN 1006, Cassiopeia A, and especially SNR RXJ1713.7-3946. In all these objects the nuclear relativistic component dominates over the relativistic electron component. Then we discuss the global nonthermal effects of SNRs. The entire population of SNRs in our Galaxy collectively drives a Galactic Wind that extends halfway to the neighboring galaxies, the CRs being dynamically important. The same is probably true for the diffuse intergalactic medium around field galaxies, especially starburst galaxies. The intracluster medium in galaxy clusters contains a significant nonthermal energy fraction, more or less in equal share the result of star formation, AGN activity and cluster accretion. It should be observable in high energy gamma rays. To wherever the nonthermal component extends, it is expected to be in rough equipartition with the thermal gas. This “Nonthermal Universe” is the result of cosmic structure formation.

The 17 m diameter Major Atmospheric Gamma Imaging Telescope (MAGIC) for gamma ray astronomy from 50 GeV, the lowest threshold achievable by such kind of telescopes, has been taking data regularly with a very high duty cicle since its commissioning phase. The status of the telescope, the results for the 1^st year of regular data taking and the outlook of the project will be reviewed.

Ashra (All-sky Survey High Resolution Air-shower detector) ^1–3 is a project to build an unconventional optical telescope complex that images very wide field of view, covering 80% of the sky, yet with the angle resolution of 1.2 arcmin, sensitive to the blue to UV light with the use of image intensifier and CMOS technology. The project primarily aims to observe Cherenkov and fluorescence lights from the lateral and longitudinal developments of very-high energy cosmic rays in the atmosphere. It can also be used to monitor optical transients in the wide field of sky. In 2004 we built prototype telescopes to verify and develop techniques at Haleakala in Hawaii, needed for the development of the full-scale telescopes. Construction of the main detector station has begun at Mauna Loa on the Hawaii Island in the summer of 2005.

We study the emission from an old supernova remnant (SNR) with an age of around 10⁵ yrs. When the SNR age is around 10⁵ yrs, hadron acceleration is efficient enough to emit TeV γ-rays at the shock of the SNR. The maximum energy of primarily accelerated electrons is so small that TeV γ-rays and X-rays are dominated by hadronic processes, π⁰-decay and synchrotron radiation from secondary electrons, respectively. However, if the SNR is older than several 10⁵ yrs, there are few high-energy particles emitting TeV γ-rays because of the energy loss effect and/or the wave damping effect occurring at low-velocity isothermal shocks. It is found that the ratio of TeV γ-ray (1–10 TeV) to X-ray (2–10 keV) energy flux can be more than ∼ 10². Such a source showing large flux ratio may be a possible origin of recently discovered unidentified TeV sources.

The CALorimetric Electron Telescope, CALET, mission is proposed for the Japanese Experiment Module Exposed Facility, JEM-EF, of the International Space Station. The mission goal is to reveal high-energy phenomena in the universe by carrying out a precise measurement of the electrons in 1 GeV - 10 TeV and the γ-rays in 20 MeV - several TeV. The CALET has a unique capability to measure the electrons and gamma-rays over 1 TeV since the hadron rejection power might be as much as ∼10⁶ and the energy resolution of electromagnetic particles better than a few % over 100 GeV. Therefore, it is promising to detect the change of energy spectra and the γ-ray line expected from candidates of the dark matter. We are expecting to launch the CALET around 2012 by the Japanese H-II Transfer Vehicle, HTV, and to observe for three years.

Suzaku is the fifth in the series of Japanese astronomy satellites devoted to observations of celestial X-ray sources launched on a Japanese M-V rocket on July 10, 2005. Suzaku features the excellent X-ray sensitivity, with high throughput over a broad-band energy range of 0.2 to 600 keV. Suzaku's broad bandpass, low background, and good CCD resolution makes it a unique tool capable of addressing a variety of outstanding problems in astrophysics.

No abstract received.

In this article, I review the current understanding of the mechanism of core-collapse supernovae, one of the most energetic events in the present universe. I will not only summarize the neutrino-heating mechanism, the standard paradigm at present, but also pay special attention to the recent topics such as the standing accretion shock instability and the acoustic revival scenario proposed by Burrows very recently.

Sensitivity of the Super-Kamiokande detector to supernova neutrinos and preliminary analyses of supernova neutrinos are presented.

I discuss neutrino production in supernovae (SNe) and the detection of both Galactic core collapse events and the diffuse extra-galactic MeV neutrino background expected from the integrated history of star formation. In particular, I consider what processes might affect our expectations for both. I focus on “rapid” rotation, defined as leading to millisecond initial neutron star spin periods. Rotation affects the neutrino luminosity, the average neutrino energy, the duration of the Kelvin-Helmholtz cooling epoch, and the ratios of luminosities and average energies between neutrino species; it can strongly suppresses the as well as , and fluxes relative to ν_e. As a result, depending on the prevalence of rapid rotation in SN progenitors through cosmic time, this may affect predictions for the MeV neutrino background and the history of nucleosynthetic enrichment. I emphasize connections between the MeV neutrino background and tracers of the star formation rate density at high redshift in other neutrino and photon wavebands.

INTEGRAL is an orbital observatory covering a broad energy range from keVs to MeVs. Its strongest features are sensitive imaging in hard X-rays (15–100 keV) and ultra-fine spectroscopy of gamma-ray lines. We present selected results of INTEGRAL observations in 2003–2006 on such subjects as positron annihilation in the Milky Way, activity of the central Galactic black hole in the recent past, Galactic absorbed X-ray sources, statistics of nearby AGN and the cosmic X-ray background.

The Atmospheric Cherenkov Imaging Technique has opened up the gamma-ray spectrum from 100 GeV to 50 TeV to astrophysical exploration. The development of the technique (with emphasis on the early days) is described as are the basic principles underlying its application to gamma-ray astronomy. The current generation of arrays of telescopes, in particular, VERITAS is briefly described.

JEM-EUSO mission is the science mission to detect extreme energy particles with the energy above 10²⁰ eV from the orbit. It is attached to Japanese experiment module of International Space Station. The outline of the mission is presented in the present paper.

We develop a new numerical method for simulations of the arrival distribution of Ultra-high Energy Cosmic Rays (UHECRs) above 10¹⁹ eV, taking their propagation in a structured magnetic field into account. This method enables us to save the CPU time greatly. Using this method, we calculate the propagation of UHE protons considering both a structured extragalactic magnetic field (EGMF) and the Galactic magnetic field, and simulate the arrival distribution. Our models of EGMF and UHECR source distribution reflect structures observed around the Milky Way. As an application, we compared our simulated arrival distribution with that observed by Akeno Grand Air Shower Array (AGASA) statistically. From this comparison, we find that the most appropriate number density of UHECR sources that best reproduces the AGASA observation is 10^–4 – 10^–5 Mpc^–3, dependent on source types.

In the standard model of GRBs, protons can be accelerated as well as electrons. Through the photomeson reaction, such protons can produce high energy neutrinos, which may be detected by large Čherenkov detectors such as IceCube. We have carried a systematic and much more thorough calculation than past work analyses of this neutrino emission to determine the high energy neutrino background from GRBs. By executing the Monte Carlo simulation kit Geant4, we can take account of pion-multiplicity and proton-inelasticity, and investigate those effects. We also find that the obtained neutrino background can be comparable with the prediction of Waxman & Bahcall without supposing the enough large nonthermal baryon loading factor necessary for the assumption that GRBs are the main sources of UHECRs. We will discuss the constraints on the nonthermal baryon-loading factor and the effects of magnetic fields.

Detection possibility of ultra high-energy (UHE) neutrino (E >10¹⁵ eV) in natural huge rock salt formation has been studied. Collision between the UHE neutrino and the rock salt produces electromagnetic (EM) shower. Charge difference (excess electrons) between electrons and positrons in EM shower radiates radio wave coherently (Askar'yan effect). In this paper, detection possibility of Salt Neutrino Detector (SND) was studied using SND simulator including attenuation length, background noise and bandwidth of antennae.

Ultra high energy (UHE ) neutrinos (E > 10¹⁵ eV) exist at any rate due to presence of the cosmic microwave background and UHE cosmic rays implied by Greisen, Zatsepin and Kuz'min (GZK). The low rate of GZK neutrinos requires us to utilize a large mass (> 50 Gton) of detection medium. The UHE neutrino generates a huge number of unpaired electrons in rock salt. They would emit sensible radio wave by coherent Cherenkov effect (Askar'yan effect). Attenuation lengths of natural rock salt samples including synthesized one at 0.3 and 1.0 GHz were measured to find a suitable site constructing a salt neutrino detector. The result indicates a possibility for constructing the salt neutrino detector with economical antenna spacing.

Recent advances in understanding of magnetohydrodynamic (MHD) turbulence call for revisions in the picture of particle acceleration. We make use of the recently established scaling of slow and fast MHD modes in strong and weak MHD turbulence to provide a systematic study of particle acceleration in magnetic pressure (low-β) and gaseous pressure (high-β) dominated plasmas. We consider the acceleration by large scale compressions in both slow and fast particle diffusion limits. We establish that fast modes accelerate particles more efficiently than slow modes. We find that particle acceleration by pitch-angle scattering and TTD dominates acceleration by slow or fast modes when the spatial diffusion rate is small.

Recently the HEAT collaboration has been reported the anomaly about the positron excess in the comic ray. The anomaly attracts attention because it may originate in the dark matter annihilation in the galactic halo. In this letter, I would like to address about the interesting fact that the SU(2)_L-triplet dark matter can explain the anomaly with satisfying the present dark matter abundance observed by WMAP. When the mass of the dark matter is around 2 TeV, which is favored from the thermal relic abundance, the non-perturbation effect significantly enhances the annihilation cross section into positrons in the non-relativistic limit. We show that the effect enables us to account for the HEAT anomaly.

High-energy photons from pair annihilation of dark matter particles contribute to the cosmic gamma-ray background (CGB) observed in a wide energy range. The precise shape of the energy spectrum of CGB depends on the nature of dark matter particles. In order to discriminate between the signals from dark matter annihilation and other astrophysical sources, however, the information from the energy spectrum of CGB may not be sufficient. We show that dark matter annihilation not only contributes to the mean CGB intensity, but also produces a characteristic anisotropy, which provides a powerful tool for testing the origins of the observed CGB. We show that the expected sensitivity of future gamma-ray detectors such as GLAST should allow us to measure the angular power spectrum of CGB anisotropy, if dark matter particles are supersymmetric neutralinos and they account for most of the observed mean intensity. As the intensity of photons from annihilation is proportional to the density squared, we show that the predicted shape of the angular power spectrum of gamma rays from dark matter annihilation is different from that due to other astrophysical sources such as blazars, whose intensity is linearly proportional to density. Therefore, the angular power spectrum of the CGB provides a “smoking-gun” signature of gamma rays from dark matter annihilation.

We numerically simulate neutrino and photon emission originated from accelerated protons in gamma-ray bursts (GRBs). Pion and kaon production via photomeson processes results in characteristic spectra of neutrinos and photons, which inform us on the physical situations and proton-acceleration efficiency in GRBs.

We address the problem of turbulence damping and particle acceleration in Solar flares. We consider turbulent energy cascade of fast modes and their collisional and collisionless damping processes, which also include damping through the transfer of turbulent energy to non-thermal particles. We identify collisionless damping by thermal particles as the dominant process for damping of fast modes in Solar corona conditions. This makes it possible to decouple particle acceleration and turbulence damping, which simplifies the problem substantially. We estimate the effect of particle acceleration on the cascade of fast modes, and show that our approach provides sufficiently accurate results.

CANGAROO-III consists of four telescopes installed near Woomera, South Australia to observe celestial gamma-ray sources by detecting Cherenkov light from air showers. Stereo observations have been performed since March 2004 with an improved angular resolution and a lower energy threshold. In this paper, we present some preliminary results from optical measurements with a cooled CCD camera on the reflectivity of the telescope reflector and the atmospheric transmittance.

We studied Cassegrain-type telescope design for IACTs to reduce the weight and cost of the telescope, keeping currently achieved optical performance of Imaging Air Cherenkov Telescopes (IACTs) in spot size, field of view, light collection performance. In addition to currently used prime-focus type telescope design, Classical Cassegrain and Ritchey-Chrétien Cassegrain optical system have been evaluated by using of an aberration theory and a ray-tracing method. We found that, in some ideal cases, the Ritchey-Chrétien optics can reduce the length of telescope down to 20% of the prime-focus optics of the same spot size at 1 degree incident angle, whereas the loss of light by the secondary mirror shadow and the second reflection is about 20% assuming a reflectivity of 85%.

We calculate cyclotron lines in a neutron star slab assuming a non-dipole surface magnetic field. We study the influences of the non-dipole surface field on the properties of cyclotron resonant scattering lines. When the magnetic field strength decreases with height in the line-forming region, the ratios of the higher harmonics to the fundamental at the peak energies of the cyclotron lines become more than the integer values. On the other hand, when the magnetic field strength increases with height in the line-forming region, the ratios at the peak energies of the cyclotron lines become less than the integer values. The nonharmonicity, which has actually been observed in some accretion-powered X-ray pulsars, is more significant than that expected from relativistic effect in cyclotron resonant energy. This may suggest the line-forming region threaded by the strong nondipole magnetic field in some accreting X-ray pulsars. In observations, the ratios are more than or less than the integer values. This could imply that the magnetic field strength in the line-forming region decreases or increases with the altitude or the horizontal distance from an emission region.

Population III stars are thought to be very massive stars. However, their properties are not clarified yet. In this research, we investigate the features of magnetorotational dynamics of such stars with computer simulations. We find jet-like explosion in a few models and reveal what type of initial model undergo explosion. In addition, we inquire features of newborn black holes as a remnant of core-collapse.

We calculate explosive nucleosynthsis induced by relativistic jets in Population III stars with 2-dimensional special relativistic hydrodynamics code. The resulting yields are compared with the abundance patterns of extremely metal-poor stars. Extremely metal-poor stars in Galactic halo, whose metallicities are much smaller than the Sun ([Fe/H] < -3), have been extensively observed. These stars are classified by their metallicities, i.e., extremely metal-poor (EMP: −4 < [Fe/H]< −3 and [C/Fe] ∼ 0), carbon-rich EMP (CEMP: −4 < [Fe/H]< −3 and +1 < [C/Fe]), and hyper metal-poor (HMP: [Fe/H]< −5 and [C/Fe]~ +4) stars. The abundance patterns of these stars have been reproduced by 1-dimensional mixing-fallback model in the previous studies. Though the differences among the EMP, CEMP, HMP stars have been well-explained by the different mixing region and ejection factor, it has not been clear what causes these differences. In this study, we show that the yields of 2-dimensional jet-like explosions give good agreements with the abundance patterns of EMP, CEMP, HMP stars and that an energy injection rate from the central engine plays an important role in producing the differences among EMP, CEMP, HMP stars.

We calculate evolution, explosion, and nucleosynthesis of 500M_⊙ and 1000M_⊙ stars. Even such massive stars may explode at the end of their lives if they rotate. We use a 2 dimensional hydrodynamical code to take aspherisity into account. Our results show that (1) abundance pattern of ejected matter by explosion is consistent with observational data of intracluster medium gas, and M82 hot gas, (2) such massive stars can supply sufficient UV photons when one considers their contribution to the re-ionization of the universe with chemical evolution, and (3) final black hole mass is 500 solar-mass for 1000M_⊙ star model, which is consistent of the mass scale of intermediate-mass black hole (IHBH) identified in M82.

The properties of the unique Type Ib supernova (SN) 2005bf are studied through the theoretical modeling of the early phase spectra and the light curve. The high velocity FeII lines in the earliest spectra are not the consequence of a jet-like explosion, but are naturally explained by a lower ionization state of Fe in the outermost layer due to the existence of the hydrogen. The velocities of the He lines measured from the position of the absorption minimum increase with time. Such a behavior is unprecedented, and can be understood if ⁵⁶Ni is not fully mixed with the He layer. An increasing deposition of γ-rays in the He layer is necessary to produce more and more non-thermal electrons. Therefore it is also suggested that the C+O layer between ⁵⁶Ni and the He layer is not very thick. The progenitors of Type Ib supernovae (SNe) and Type Ic SNe are briefly discussed by comparing SN 2005bf with other Type Ib/c SNe. We suggest that the mixig of ⁵⁶Ni plays an important role to make the difference between Type Ib SNe and Type Ic SNe.

We investigate thermal and dynamical behavior of an optically thin two-temprature accretion plasma in a simplified one-zone model. We compute time development of a plasma which is located at a certain radius suffering from a constant frictional heating and bremsstrahlung cooling. When pair production is not taken into account, we find that equilibrium states are possible only for a certain range of surface density for a given heating rate. For a small surface density the proton temperature becomes so high that the plasma escapes from the gravitational potential of the central black hole to form an outflow. For a large surface density, the plasma cannot bear gravity force and collapses towards a low temperature and high density state. When the pair production is taken into account, pair concentration increases with heating rate, maintaining the balance between pair production and pair annihilation even for high heating rates. This result is in contrast to that of Kusunose and Takahara(1988), where no pair equilibrium states were found for high accretion rates. We discuss possible reasons for this difference and suggest that pair concentration in two-temperature accretion plasma depends sensitively on detailed plasma profile.

The CLIO is a 100 m baseline cryogenic laser interferometer for the detection of the gravitational waves, which is under construction in Kamioka mine, Japan. This is for the investigation the technical feasibility for the Large-scale Cryogenic Gravitational wave Telescope (LCGT), which is planned to be constructed in the same Kamioka mine with 30 times longer baseline than the CLIO. We successfully operated CLIO, whose three mirrors were cooled around 20K, as a gravitational wave detector using a locked Fabry-Perot control scheme.

We developed an automatic measuring device of birefringence inhomogeneity in synthetic sapphire substrates to evaluate their crystal quality suitable for laser interferometric gravitational wave (GW) detectors. The phase retardation was measured with an accuracy of 7 × 10⁻⁴ rad and the orientation of the fast axis with an accuracy of 2 × 10⁻² rad. The automatic measuring device is useful to check the inhomogeneity of substrates for the LCGT project, which is a next-generation laser interferometer project for GW detection.

We provide a fitting function for quasar luminosity function based on several sets of recent optical observations including SDSS DR3. From that luminosity function, together with black hole mass function, we estimate radiation efficiency of quasars. We also discuss implications from X-ray observations.

Scientific Program.